1. Field of the Invention
The invention relates to a composite plain thrust journal bearing having a journal bearing part in the form of a half-liner or bush on one or both sides of which is mounted a ring-part shaped thrust bearing part or a set of thrust bearing parts, every thrust bearing part having at is inner peripheral edge at least two retaining lugs, each of which engages into a recess provided in the region of the arcuate or circular rim of the journal bearing part, at least one retaining lug being flanked, as an attachment lug, with at least one splay finger, which engages in an undercut made in the associated attachment recess of the journal bearing part.
2. Description of Prior Developments
Composite plain thrust journal bearings are known from a number of prior publications. They have an advantage in comparison with a one-piece plain thrust journal bearing (flange bearing) in that a different material may be chosen for the journal bearing part than for the thrust bearing part so that an optimum material adaptation to particular loading conditions is possible. To keep the wear of the parts in the composite plain thrust journal bearing low, centering and fixing of the bearing parts with respect to each other is of great importance, while a certain movability of the thrust bearing part with respect to the journal bearing part is desirable at least for the assembly of the plain bearing.
From EP 298 953 B 1 is known such a plain thrust journal bearing composed of a half-liner and a separate thrust flange, in which, for the attachment of the thrust flange to the half-liner, the latter is provided with insertion recesses which are open towards the outer rim and form an undercut in the form of a dovetail effective in the axial direction. On the thrust flange are provided fixing extensions which correspond to these insertion recesses and which are formed by tongues bent in an axial direction. In these known plain thrust journal bearings the retaining lugs must be very long and bent very accurately. For the connection of the thrust flange to the bearing liner the thrust flange is slipped over the bearing half-liner in a radial direction. If all fixing extensions corresponding to the insertion recesses have dovetail form, it is necessary to elastically deform the bearing half-liner by compression such that the fixing extensions may be inserted into the fixing recesses. Apart from the fact that damage can be caused by this elastic deformation to the shape and coating of the bearing half-liner, such an elastic deformation is at all possible only with bearing half-liners and not with bearing bushes.
In EP 298 953 B 1 is therefore considered a second possibility for the insertion of the fixing extensions into the insertion recesses in that a central fixing extension is first formed rectangularly and with preformed splay fingers and, after positioning of the thrust flange on the bearing half-liner, these splay fingers are widened into the dovetail form of the insertion recess. This widening in the dovetail form is difficult in the case of bent fixing extensions and brings with it the danger of damage to the journal bearing part. In addition the parts of a fixing extension bent to the dovetail form bring about only conditional strength and reliability of attachment because they act inside the dovetail-shaped insertion recess only as wedge-shaped retaining elements which are deformed during relative movement between the thrust flange and the journal bearing part and are thereby increasingly loosened in the insertion recess.
From the later published older German Patent Application DE 41 40 277 A1 is also known a composite plain thrust journal bearing in which a retaining lug of the thrust bearing part, serving as an attachment lug, is inserted into a closed retaining opening formed in the peripheral rim of the journal bearing part and subsequently is shaped into a nose extending over the journal bearing part. This can ensure a reliable and lasting holding and defined limitation of the axial spacing of the thrust bearing part with respect to the journal bearing part, but formation of the nose on the attachment lug requires high accuracy and exceptional care to avoid damage to the bearing parts.